A computer system includes central processing units designed by using reduced instruction set computing (RISC) strategy, dynamic random access memory (DRAM) packages manufactured by using three-dimensional integrated circuit (3D IC) stacked using through-silicon via (TSV) stacking processes, and liquid cooling approach. The system has advantages of low power consumption, fast DRAM access rate, high performance, high cooling efficiency, small form factor, and low costs. Cooling liquid could be water, oil, and ionic liquid. The heat generated in 3D IC chips is carried out by liquid coolant and dissipated to heat exchanger where cooling water dissipates heat to large water body such as river, reservoir, or ocean. The computer disclosed in this invention is suitable to be a server for application in datacenter.